61. In case ofsensible cooling of air, the coil efficiency is given by
B.P.F. – 1
1 – B.P.F.
1 + B.P.F.
✅ The correct answer is option B.
Heat Transfer, Refrigeration and Air Conditioning MCQs
62. The fluids used in electrolux refrigerator are
water and hydrogen
ammonia and hydrogen
ammonia, water and hydrogen
none of these
✅ The correct answer is option C.
63. The superheated vapour region, in a pressure enthalpy chart, is represented by the space
to the left of saturated liquid line
to the right of saturated liquid line
between the saturated liquid line and saturated vapour line
none of the above
✅ The correct answer is option C.
65. The air cooling system mostly used in transport type aircrafts is
simple air cooling system
simple evaporative air cooling system
boot-strap air cooling system
all of these
✅ The correct answer is option C.
66. During heating and humidification, the final relative humidity of air
is higher than that of the entering air
is lower than that of the entering air
can be lower or higher than that of the entering air
none of the above
✅ The correct answer is option C.
67. The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure, is called
humidity ratio
relative humidity
absolute humidity
degree of saturation
✅ The correct answer is option D.
68. Relative humidity is given by (where pv = Partial pressure of water vapour, pb = Barometric pressure, ps = Pressure of saturated air, pd = Pressure at dry bulb temperature, pw = Saturation pressure corresponding to wet bulb temperature, and μ = Degree of saturation)
none of these
✅ The correct answer is option B.
69. The relative humidity __________ as air gets drier.
increases
decreases
✅ The correct answer is option A.
70. During sensible cooling of air, the relative humidity increases.
Yes
No
✅ The correct answer is option A.